Quantum Key Distribution System to Overcome Intercept-Resend and Detector-Control Quantum Hacking

5. The system of claim 4, wherein the state converter includes a polarization converter in an arm of the interferometer to rotate light within the arm to an orthogonal polarization.

6. The system of claim 4, wherein the state converter includes an additional phase modulator in one arm of the interferometer, wherein the additional phase modulator leaves the faint pulse from the light source to be transmitted to the quantum bit encoder unchanged, wherein the additional phase modulator imparts a phase shift between the leading time bin and the lagging time bin of the return pulse.

7. The system of claim 6, wherein the phase shift imparted by the additional phase modulator is associated with an encoding basis, wherein the phase shift is one of 0 or π on a first basis and one of π/2 or 3π/2 on a second basis, wherein the encoding basis is one of the first basis or the second basis.

8. The system of claim 7, wherein the transceiver determines an encoded bit of the one or more encoded bits provided by the quantum bit encoder if the encoding basis matches the encoding basis used by the phase modulator in the quantum bit encoder.

9. The system of claim 7, wherein the three or more detectors are configured to measure polarization in a diagonal basis relative to the encoding basis.

10. The system of claim 4, wherein triggering of any detector in the second detector subset indicates a presence of the faked-state pulse.

11. The system of claim 10, wherein triggering of any detector in the second detector subset indicative of the presence of the faked-state pulse comprises a single-sided determination of the presence of the faked-state pulse by the transceiver.

12. The system of claim 4, wherein the first detector subset includes at least two detectors, wherein the transceiver determines an encoded bit of the one or more encoded bits provided by the quantum bit encoder based on which detector in the first detector subset is triggered.

13. The system of claim 12, wherein at least one of the transceiver or the quantum bit encoder utilize the encoded bit when generating an encryption key.

14. The system of claim 13, wherein at least one of the transceiver or the quantum bit encoder utilize the encoded bit when generating the encryption key using a BB84 protocol.

15. The system of claim 4, wherein the mirror is a Faraday mirror, wherein the Faraday mirror rotates a polarization of the faint pulse to an orthogonal state.

16. The system of claim 4, wherein the polarization randomizer is a reciprocal polarization randomizer with a continuum of possible random realizations based on a Haar measure.

17. The system of claim 4, wherein the polarization randomizer maintains the random polarization transformation during a round-trip time of the faint pulse between the transceiver and the quantum bit encoder.

18. The system of claim 4, wherein the polarization randomizer provides the random polarization transformation for a set of time windows, wherein constituent windows in the set of time windows are separated by a round-trip time of the faint pulse between the transceiver and the quantum bit encoder and synchronized with the transmission of the faint pulse by the transceiver.

19. The system of claim 18, wherein the polarization randomizer provides additional polarization transformations for additional sets of time windows, wherein constituent windows in each of the additional sets of time windows are separated by the round-trip time, where the additional sets of time windows are synchronized to additional faint pulses transmitted by the transceiver.

20. The system of claim 4, wherein the transceiver further includes a polarization switch between the polarization randomizer and the state converter, wherein the polarization switch leaves a polarization of the faint pulse to be transmitted to the quantum bit encoder unchanged, wherein the polarization switch applies an additional random polarization transformation to the faint pulse, wherein the additional random polarization transformation includes one of passing the faint pulse unmodified or rotating polarization by 90 degrees, wherein the first detector subset is determined based on the random polarization transformation from the polarization randomizer and the additional random polarization transformation from the polarization switch.

21. The system of claim 4, wherein the first detector subset is associated with a first exit path of the interferometer, wherein the second detector subset is associated with a second exit path of the interferometer.

25. The system of claim 24, wherein the state converter includes an additional phase modulator in one arm of the interferometer, wherein the additional phase modulator leaves the faint pulse from the light source to be transmitted to the quantum bit encoder unchanged, wherein the additional phase modulator imparts a phase shift between the leading time bin and the lagging time bin of the return pulse, wherein the phase shift imparted by the additional phase modulator is associated with an encoding basis, wherein the phase shift is one of 0 or π on a first basis and one of π/2 or 3π/2 on a second basis, wherein the encoding basis is one of the first basis or the second basis, wherein the three or more detectors are configured to measure polarization in a diagonal basis relative to the encoding basis.

26. The system of claim 25, wherein the transceiver determines the encoded bit provided by the quantum bit encoder if the encoding basis matches the encoding basis used by the phase modulator in the quantum bit encoder.

27. The system of claim 24, wherein triggering of any detector in the second detector subset indicates a presence of the faked-state pulse.

28. The system of claim 24, wherein the first detector subset includes at least two detectors, wherein the transceiver determines the encoded bit provided by the quantum bit encoder based on which detector in the first detector subset is triggered, wherein at least one of the transceiver or the quantum bit encoder utilize the encoded bit when generating an encryption key.

29. The system of claim 24, wherein the polarization randomizer maintains the random polarization transformation during a round-trip time of the faint pulse between the transceiver and the quantum bit encoder.

30. The system of claim 24, wherein the polarization randomizer provides the random polarization transformation for a set of time windows separated by a round-trip time of the faint pulse between the transceiver and the quantum bit encoder and synchronized with the transmission of the faint pulse by the transceiver, wherein the polarization randomizer provides additional polarization transformations for additional sets of time windows separated by the round-trip time, where the additional sets of time windows are synchronized to additional faint pulses transmitted by the transceiver.

31. The system of claim 24, wherein the transceiver further includes a polarization switch between the polarization randomizer and the state converter, wherein the polarization switch leaves the polarization of the faint pulse to be transmitted to the quantum bit encoder unchanged, wherein the polarization switch applies an additional random polarization transformation to the faint pulse, wherein the additional random polarization transformation includes one of passing the faint pulse unmodified or rotating polarization by 90 degrees, wherein the first detector subset is determined based on the random polarization transformation from the polarization randomizer and the additional random polarization transformation from the polarization switch.

32. The system of claim 24, wherein the first detector subset is associated with a first exit path of the interferometer, wherein the second detector subset is associated with a second exit path of the interferometer.